Counterbalancing actuator for doors and the like



. Sept. 10, 1940.

o. T. FRASCH COUNTERBALANCING ACTUATOR FOR DOORS AND THE LIKE 3 Sheets-Sheet 1 Filed Oct. 5, 1937 Sept. 10, 1940. Q T FRASCH 2,214,229

COUNTERBALANCING ACTUATOR FOR DOORS AND THE LIKE Filed Oct. 5, 1937 V 3 Sheets-Sheet 2 Sept. 10, 1940. Q R C 2,214,229

COUNTERBALANCING ACTUATOR FOR DOORS AND THE LIKE Filed Oct. 5, 193'? 3 Sheets-Sheet 3 35 fire/7 for 01 0 754%5 Patented Sept. 10, 1940 UNITED STATES COUNTERBALANCING ACTUATOR FOR DOORS AND THE LIKE Otto T. Frasch, Los Angeles, Calif.

Application October 5, 1937, Serial No. 167,361

3 Claims.

This invention relates to and has for an object the provision of a counterbalancing actuating means for doors and the like, such as are used for garages and factories, and particularly doors that are raised from and lowered into closing position, the purpose being to facilitate the hanging and the opening and closing of such doors without appreciable manual efiort and through the instrumentality of simple and inexpensive mechanism which is capable of being readily and easily installed and operated.

Another object of this invention is to provide actuating means of the character described which, through a novel arrangement and combination of automatically variable leverage means, door hanging means and weights or springs, will provide for a substantially counterbalancing door which is operative with a substantially uniform rate of opening and closing movement whereby to prevent slamming or undesirable jarring or injury or damage to persons or obstructions in the path of movement thereof.

Another object is to provide a counterbalancing actuating mechanism of the character described which is manually started as by effecting a slight movement of a starting lever, for the purpose of causing the door to be opened or closed, the said mechanism maintaining a substantially uniform counterbalancing effect throughout the entire movement of the door, while at the same time varying the torque proportionate to the load of the door.

A further object is to provide an actuator mechanism of the character described which in- 36 cludes a novel variable leverage device connected with the door or member to be operated and with a weight, spring or the like in such manner that the aforesaid counterbalancing efiects will be obtained throughout all movements of the door 40 whereby but a slight force is necessary to effect the movement of the door or to stop such movement and hold the door in any position into which it is moved.

Yet another object is to provide an actuator 'of the character described, which makes possible an eificacious mounting of a door whereby to take up comparatively little space and offer little or no obstruction to the doorway and adjacent areas, but little overhead space being required.

I have shown a preferred embodiment of my improvements in the accompanying drawings, subject to modification, within the scope of the appended claims, without departing from the spirit of my invention.

Fig. 4 is a sectional view taken ontheplane of line 44 of Fig. 3, ,7

Fig. 51s a sectional view taken on theplane of line 5-5 of Fig. 4,

- Fig. 6 is a sectional view taken on the plane of line 6-6 of Fig. 4, I

Fig. 7 is a view similar to Fig. lof a modified form of the invention as when the door is closed,

Fig. 8 is a view similar to Fig. '7 of a mechanism shown in said figure as when the door isQp'ened,

Fig. 9 is a side elevation of the=leverage .,pu11ey employed in the form of the inventionshown in Figs? and 8,

Fig. 10 is a front elevation of the pulley shown in Fig. 9,

Fig. 11 is a view of the pulley shown in Fig. 9 taken on the opposite side thereof, V

Fig. 12 is a schematic section partially in elevation of a modifiedform of the-invention, and

Fig. 13 is a schematic plan view of another modified form of the invention. f,

One embodiment of this invention, as, shown in detail in the accompanying drawing's coniprises a door frame A having a door .3 adapted to be raised from and lowered into closingposition, as particularly shown. in Figs. 1 and 2 the door being disposed substantiallyparallel, to and below the ceiling C when in closed position In accordance with one form of this invention the door is supportedby pairs of links, orljbars D and E of which but sn er each pairisshown, the links D being pivoted as at 'F toflthe upper end of the door and extending downwardly and inwardly to points 'adjacentthe floorfG where pivoted as at H. The links" Eat their lowerlends are pivoted as at J to the lower edge offthejdoor and extend upwardly and rearwardly iridntersecting relation to the links D with'their upper ends pivoted as atKto atheside walls or' sifnilar structures L. By having these'linkspivot'ed adjacent the upper and lower edges ofth'edoor' and extending them downwardly and rearwardly and upwardly and rearwardly respectively so'fas to intersect, and locating the pivots K for the shorter links E substantially midway of the upper and lowerends of and well inwardly of the door, it will .be seen that the door will not project appreciably outwardly from the door opening or frame duringmovement into and out of closedposition and the mechanism does not obstruct the doorway and adjacent area.

As a means'for stopping the door in the desired opened and closed positions flexible elements M such as chains, are fixed at their ends to the links D and to the walls L, asparticularly shown in Figs. 1 and 2. On said walls L are guide bars N for holding the links D spaced outwardly of the walls sufficiently to insure the clearance of the links D with respect to the elements of the mechanism past which said links are movable. Instead of the bars E arranged, as shown in full lines in Figs. 1 and 2, I may use links which extend substantially horizontally from the pivots K to points of fixed connection with the door as at 33 in Fig. 7. These substitute links will prevent the extension of any of thehanging means through the door opening and may be desirable in some'instances. 1

As here shown the pivots K each comprise a wall carried pintle l upon which a plurality of circular clamping plates 2, 3 and 4 a're rotatably mounted. Between the plates 2 and 3'which are normally separated by opposed spacing lugs 5 and 6 the ends of the links E are clamped. These ends engage between certain of the lugs 5 and 6 on each of said plates 2 and 3 and are additionally held by bolts I passing through said plates andsaid links. The clamping action is effected by means of lag bolts 8, which passing freely 1 through apertures 3 in plates 2 and 3, have their threaded portions engaged in threaded bosses IE the desired positions between the plates 3 and 4,

as particularly shown in Figs. 3 to 6 inclusive, andprovided with. suitable bracing I2a. These actuating crank arms as here shown, v extend substantially at right angles to the links E but may be varied as to the position thereof relative to said link and each is comprised of a channel barbent into a substantial D shape the ends ofthe bar being clamped as aforesaid. One

portion of each crank arm I2 comprises an armate member I3 having an angularly extended outer portion I4 forming a joint with a straight portion I5. Flexible elements or cables -16 are secured as at I! adjacent the inner ends of the portions I3 of the crank arm I2 and lie in the channels of said portions I3, being in effect reeved around the arcuate and angular portions I3 and I4 of said crank arm. Clamps I8 may be employed to hold the flexible elements within the channels at intermediate points of the-arouate portion I3. The cables I6 extend substantially at right angles to the straight members I5 oi the crank arms and over ceiling or wall suspended adjustable pulleys I3and from thence rearwardly over fixed wall or ceiling supported pulleys 20 and then downwardly to actuating weights 2I suspended thereby. It is thus seen that the weights 2I operate through the cables I6 and the actuating crank arms I2 to rotate the clamping plates 2, 3 and 4, whereby the links E will act as crank arms and thereby cause the door to be moved. The adjustable pulley I3 is mounted,

on a pivoted hangar 22 which is connected by a" link 23 with a starting lever 24 pivoted as at 23 on a bracket 26 carried by the door frame.

In hanging the door with this mechanism the elements of the mechanism are arranged so that when the door is closed the parts will assume the positions shown in Fig. l with the weights elevatedand the door substantially counterbalanced in such manner that but a slight manually effected overbalancing will cause it to swing into up or open position. To start the mechanism it is necessary to move the lever 24 inwardly whereby the pulley I9 is shifted to the right from the position shown in Fig. 1, and the centers change so that the weights become effective through their related mechanism to aid in raising the door. It

is desired that the overbalancing factor remain substantially constant so that the door raising force of the weights is at all times during the movement of the door, but slightly in excess of the load, whereas a variable torque is desired in consideration of the varying load. To this end the portions I3 and I4 of the actuating crank arms I2 are so curved and angularly related as to vary the leverage action in consideration of the load at different positions of the door. The.

maximum leverage is secured at the initial opening movement and this leverage decreases in proportion to the decrease in the load as when the 'dooris being raised. Reversely, on the closing of the door, the leverage is at its minimum upon the start of its closing action and gradually increases as the door reaches its closed position. To enhance the maximum leverage necessary at the'start of the raising operation the crank arms I2 are provided with extensions 21 which, when the door is in closed position, will produce slight kinksin the cables l6, as shown in Fig. 1. These extensions increase the initial leverage but when the cranks have moved a slight distance after the initial opening movement of the door, said extensions are no longer effective and it is seen that due to the shape of theportions I3 and I4 of the crank arms, the leverage will decrease as said crank arms'move in correspondence with the raising of thedoor. It should be noted that a nicety of control of the action may be had by appropriate manipulation of' the leverage 24 to shift the pulley I3. When the door is in raised position it will remain in such position until. the lever is manipulated to move the pulley forwardly. This will cause the weight of the door to overcome that of the force of the weights and the door will tend to lower, but the rate of movement of the door will be substantially constant due to the increasing leverage action afforded by the crank arm as the door tends to accelerate its gravitation movement to closed position. It should be noted that by reason of the construction and arrangement of the mechanism hereof, particularly the variable leverage devices, the

door will be operated with but a small movement differs from the latter by combining variable leverage pulleys 35 with the variable leverage crank arms 36. The crank arms 34 are shown semi-diagrammatically in Figures 7 and 8, but are identical as to construction and operation with the arm I! shown in Figures 1 to 6 inclusive. Cables 36 extend from the crank arms 34 and are secured as at 31 to the inner ends of spiral grooves 38 formed in the pulleys 35. These pulleys are mounted on shafts 39 supported by hangars 40 from the ceiling 4|. Other cables 42 are connected as at 43 with the inner ends of spiral grooves 44 also formed on the said pulleys 35, and extend rearwardly and around pulleys 46 suspended from the ceiling 42 and thence downwardly to the weights 41, there being here shown but one set of cables, crank arms, pulleys and weights. The arrangement of these pulleys and cables is such that when the cables 36 are unwound, as shown in Fig. 7, the cables 42 are wound around the pulleys in the grooves 44, as shown in Fig. 8. When the door is raised, the cables 38 are wound around the pulleys in the spiral grooves 38, whereas the cables 42 are unwound. The action of these pulleys with their twin spiral grooves and the cables make possible a variable leverage and the use of comparatively small weights which move through short distances in counterbalancing the door. In this form of the invention it is seen that the door is hung so as to be counterbalanced, whereby but a slight manual efiort is required'to cause the door to be raised and lowered at a uniform rate of movement. The pulleys 35 operate as well as the crank arms 34, to vary the leverage in accordance with the load, so as to maintain a substantially balanced action with the door moving at a uniform rate. In this form of the invention the door extends but slightly outwardly through the door opening and no part of the hanging or .actuating mechanism.- :projects through said opening.

As particularly shown in Fig. 13, the form of the invention shown in Figs. '7 and 8 readily lends itself to installation in doorways which ordinarily prove difiicult in accommodating the installation of doors and actuating mechanisms. It is seen that the doorway 48 is closer to one wall 49 than to the wall 50 and under these conditions it is only necessary to provide a lateral extension 5| for the door 52 and connect the links 32 and 33 on one side of the door with the outer end of this extension, the hanging and actuating mechanism being otherwise as shown in Figs. '7 and 8.

As shown in Fig. 12 the modified form of the invention includes a flexible door 53 operating like a roll-top desk and having a flexible element or cable 54 connected with the lower end thereof and 'with a variable leverage device 55 corresponding for example, to the device l2 shown in Fig. 1. The variable leverage device 55 is mounted on a ceiling supported shaft 55 which also supports a second variable leverage device 51. The-device 5'! is connected with a cable 58 which extends around a pulley 59 and supports a weight 60. The two devices 55 and 51 provide for a compound leverage action which varies in consideration of the load during the opening and closing movement of the door and maintains a substantially balanced action as in the other forms of the invention. This form of the invention indicates that the variable leverage action may be multiplied by using a plurality of variable leverage crank arms and it is obvious that the use of a plurality of such crank arms may be carried out if desired in connection with the other forms of the invention.

In the form of the invention shown in Figs. 1 and 2, it will be possible to eliminate the actuating lever 24 and associated elements and operate the door manually. In this arrangement the hangers 22 are swung to dispose the pulleys I9 in the proper positions to counterbalance the door and are then fixed in said proper positions as by inserting fastenings, not shown, through the openings 22' in said hangers and into the wall or the structure opposite thereto. When the pulleys H) are thus fixed the door is operated manually instead of by shifting the pulleys as in the form of the invention shown in Figs. 1 and 2.

I claim:

1. An actuator for doors and the like, comprising a support, a plurality of clamping plates rotatably mounted onsaid support, an actuating crank arm clamped between and held by certain of said plates, a flexible element connected with the crank arm at a point remote from the free end thereof and adapted to extend around said free end, a counterbalancing weight means operatively associated with said flexible element and a door actuating crank arm clamped between certain of said plates and arranged for connection with the door to be actuated, and means for securing said plates in clamping relation to said crank arm, being adjustable to permit of securing said crank arms in relative positions.

2. In an actuator for doors and the like, a rotatable pulley having separate spiral grooves, flexible elements secured to said pulley and arranged so that when one of them is wound around. the pulley in one of said grooves, the other will be unwound with relation to said other groove, a weight connected with one of said flexible elements, an actuating crank arm, a support for the last named crank arm, a door actuating crank arm operatively associated with said first named crank arm and adapted for connection with a door, the other of said flexible elements being connected with said first named crank arm.

3. In an actuator for doors and the like, a rotatable pulley having separate spiral grooves, flexible elements secured to said pulley and arranged so that when one of them is wound around the pulley in one of said grooves the other will be unwound with relation to the other groove, counterbalancing means connected with one of said flexible'elements for maintaining the same under tension at all times, an actuating crank arm, and door actuating means connected with the other of said flexible elements and said actuating crank.

O'I'IO T. FRASCH. 

